Hydraulically operated paper cutter



1953 J. ADRIAN 2,649,154 HYDRAULICALLY OPERATED PAPER CUTTER Filed Aug. 26, 1950 s Sheets-Sheet 1 INVEN TOR. Joseph Adrian wwvmmwm 1953 J. ADRIAN 2,649,154

. HYDRAULICALLY OPERATED PAPER CUTTER Filed Aug. 26, 1950 5 Sheets-Sheet 2 Fig. 2

I N V E N TOR. Joseph Adrian BY QMJLTQLASLM 1953 J. ADRIAN 2,649,154

HYDRAULICALLY OPERATED PAPER CUTTER Filed Aug. 26, 1950 5 Sheets-Sheet 3 IN V EN T 0R. Joseph Adrian BY VOIUSZWQN Aug. 18, 1953 J. ADRIAN 2,649,154

HYDRAULICALLY OPERATED PAPER CUTTER Filed Aug. 26, 1950 Fig.5

Mlillili 64b 60b 0 INVENTOR. Q 66 Joseph Adrian Alfys.

Aug. 18, 1953 J. ADRIAN HYDRAULICALLY OPERATED PAPER CUTTER 5 Sheets-Sheet 5 Filed Aug. 26, 1950 INVENTOR. Joseph Adrian Patented Aug. 18, 1953 TED STATE-S- PATENT 0 FF ICE 2,649,154 HYDRAULICALLYOPER'ATED PArER CUTTER Joseph Adrian, Cleveland, Ohio, assignorto Super Speed Printing Machinery, Inc, Gleveland,- Ohio; a corporation ofOhio Application August 26,1950, sari-ain't.- 181,631 s= Claims. (01. 164-56) This application is a continuation inpart of my abandoned application Serial No. 161,775, filed" May 13, 1950, and entitled Hydraulic E uament or Paper Cutters.

The invention, in its more comprehensive aspect, resides in improvements in paper cutters of the kind that are used, for example, in' printing establishments; while, in a more limited phase, it has to} do with an adjunct or attachment for such machines.

In p'ap'er' cutters of the kind with which my invention is concerned, the knife travels between a top position, wherein its cutting edge is above the clamp, common in such machine for holding the work in place" upon the table, and a bottom position wherein said edge is embedded more or less in the cutting stick. While it is desirable to be able'to stop" the knife bar in an intermediate position during the downstroke to facilitate' replacing or adjustment of the knife, a danger results irom the ability to stop the knife on it's upstroke before its cutting edge is above the bottom plane of the clamp, said clamp serving, when the knife edge is above said plane, to guard the operators hands from contact with the cutting edge., For instance, if an operator were cutting a shallow stack of sheet material, such as paper or cardboard, and in his haste to lift the stack from the machine or rearrangeit for further cutting, and after retracting the clamp, he raised the knife only enough to clear the: stack, he would expose himself to the danger of cutting his hands on the knife. 7

It is a purpose of my inventicn, therefore, to" provide a ccntrivance that functions automatically to prevent the knife from being stopped in" its" upward travel before it reaches'the top limit of its stroke.

Another object of the invention is to provide hydraulic means or equipment for operating the knife bar of apaper cutter, characterized. by an hydraulically operated contrivance for preventing stop-page of the knife bar during its upward stroke.

Anoti-ier object is to provide a contriva-nce of the character described that is thoroughly reliable"; that is simple and substantial of constructiori; that is very du'rahle'in service, and that is not liable t-d-get out of order.

A furtherohject o f-the invention is'to provide hydraulic-equipment, in the natureof an adjunct or attachment, by means of which manually 2, machines-.- Accordingly, by virtue of the invention, poweroperated; paper cutters are made availableto the smaller printing concerns which, heretofore, have found an investment insuch machines impractical from aneconomic standpoint, or the cost actually prohibitive; Prev-ailing machinesof this class-that is, hydraulically operatedpapercutters-are usually large and ex pensive and; furthermore,. are of a capacity far exceeding the requirements of the smaller printing concerns; A printer whopossesses a manually opera'ted: paper-cutter of the character with which theequ-ipment oin'iy invention is designed for use may procure said equipmentand installit in his machine at relatively low' cost.

Another object of the invention is to provide hydraulic equipmentof the nature aforesaid that requires only a few simple changes in" the paper cutter, and a minimum number of connections between the equipmentand the machine.

Another object of the inveiition is to provide equipment of the above mentionedecharacter that is safe in this. respect, that it protects the hands of the operator from injury by the knife during a cutting operation-because'it requires the simulthe knife bar may be stopped in any position during its down-ward stroke thereby to facilitate removal'and replacement ofthe knife, as well as accurate adjustment-ofthe latter with respect to the-knife bar.

Also, it is' anobject of theinvention to so design the equipment that, upon its being properly installed, it Will-preventthe knife from penetrating the eutting-stick-to an; appreciable depth, makingthe use of a? special stop for this purpose op' 'e fatedfpaper cutters may be easily, quickly and relatively inekpierisively converted raw ower unnecessary:

A stillfurther and'inore detailed object of the invention is to-p'rovide hydraulic equipment for converting mama-11 operated" paper cutters into power machines, comprisin'ga cylinder and'piston lever, shaft, p'ullar'm andco'nnecting link), and

' and distinct-power unit assembly (in.- eorp'siaen ail electric motor; pump, tank, valve,

3 operating handle for the latter, automatic means for retaining said handle in knife retracting position until the knife reaches the top limit of its movement, and a latch for controlling the movement of the said handle in a direction to effect a downstroke of the knife) which power unit assembly may be placed, desirably upon the floor, in such relation to the paper cutter that the valve operating handle of said equipment is located in convenient reach of the operator as, for example, immediately below the front of the table, and with the actuator of the aforesaid latch attached to an appropriate part of the machine, as the front of said table in laterally spaced relation to the valve operatin handle. The connection between the actuator and latch, and the conduits or hoses through which communicative connections are made between the power unit assembly and the cylinder, are flexible and of maximum required length, thereby affording considerable latitude in the relation of the power unit assembly to the paper cutter.

The foregoing objects, with others hereinafter appearing, are attained in the embodiment of the invention illustrated in the accompanying drawings, wherein like reference characters designate like parts throughout the several views.

In the drawings, Fig. 1 represents a front elevation, Fig. 2 a side elevation, and Fig. 3 a rear elevation, of a paper cutter in which the hydraulic equipment of my invention is installed; Fig. 4 is a sectional plan, taken substantially on the line 4-4 of Fig. 1; Fig. 5 is a sectional detail of the latch, including its actuator, that controls the operation of the valve operating handle for effecting a downstroke of the knife; Fig. 6 is a schematic representation of the hydraulic equipment; Fig. 7 is a fragmentary perspective view of the hydraulic equipment, and Fig. 8 is a side elevational view of the parts shown in Fig. '7 with a portion of one of said parts broken away.

The paper cutter shown in the drawings is of a well known type, and the frame thereof comprises side members If] and II, a top cross member l2 and a center frame member I4 that is disposed between and is connected to the lower portions of the side members l and II and supports the central portion of the table 55 that is connected at its opposite sides to the frame members it! and II. The usual cutting stick iii, of wood or other impressionable material, which receives the cutting edge of the knife, reposes within a cross groove of the table [5.

Guided for vertical movement, in the top portion of the machine frame, is a knife bar I! that is supported in the usual way through parallel links Hi from the top cross member I2. 20 denotes the knife that is adjustably connected, by bolts 2!, to the knife bar I! in accordance with common practice. The conventional back gauge 25 is adjustable along the table l by a screw shaft 24, that is adapted to be turned by a hand wheel 25, and the usual clamp by which the material to be cut is secured in position on the table i5, is operated by the hand wheel 26. The clamp, shown in Fig. 3, is designated 21.

As is well known by those acquainted with the art, manually operated paper cutters are provided with a shaft, a hand lever for operating the shaft, a so-called pull arm or crank on theshaft, a connecting link between said arm or crank and the knife bar, and a weight connect in such a manner as to counterbalance the knife bar. To condition the paper cutter for the application of my hydraulic equipment, the foregoing parts are removed.

Installed in the machine, as a substitute for the manual knife operating mechanism above referred to, is a piston and cylinder assembly, designated generally by the reference numeral 39. This assembly includes a cylinder 3|, within which a piston 32 reciprocates. Rigidly connectcd to the piston is the rod 33 that operates, through the usual stuiiing box (not shown) in the upper end or head of the cylinder, and the distal end of said rod is pivotally connected, through a clevis 35, to a part 38 of the knife bar [1. Fastened to the front and rear sides of the center frame M of the machine, as by bolts 39, are mounting plates 48 (Fig. 2), tubular spacers M, and washers :32 being applied to said bolts to properly locate the mounting plates in a fore-and-aft direction. Connected, by a pivot pin 45, to the upper ends of the mounting plates 49, is the lower end of the cylinder 3|. It may be mentioned in passing that the piston and cylinder assembly 3!} extends through the opening in the side member I! of the machine frame that formerly accommodated the connecting link of the hand operated mechanism. Before drilling the holes in the center frame I4 for the bolts 39, the knife bar I! is lowered until the knife 20 rests upon the cutting stick IS. The cylinder 3! is then pushed up until stopped by the piston 32, and, with the parts of the assembly 3%! in substantial alignment and disposed in approximately the direction of movement of the knife bar, the frame member M is spotted for the drilling of the bolt holes. With the parts properly installed, the limits of movement of the knife bar are permanently established, and no further stop means or adjustments are necessary.

The power unit assembly, designated generally by the reference numeral 50, comprises a base 5! that mounts, adjacent one of its ends, an electric motor 53. Fastened to the base adjacent its other end is an angle member 55 to which is attached a plate 51. Secured to and supported by this plate is a self-contained hydraulic power unit, the one shown in Figs. 1 to 4 of the drawings being of a well known type, having a variety of applications. The unit includes a body member 69 that is fastened to the plate 51. This body member carries a rotary pump 62, the shaft of which is connected to that of the motor by a coupling 63; and a slide valve 64 is incorporated in said body member.

A cover 65 is applied to the top of the body member fill, and to the side of the latter remote from the motor 53 is attached a tank 66, having a filling opening closed by a cap 5'? that serves as a breather and contains a filter. The pump 62 is enclosed by the tank 66 and its inlet is in constant communication with a supply of hydraulic fluid or oil of suitable grade contained in the tank. The body member 69 and cover '65 are ported to establish communication between the pump and conduits or hoses S3 and 69 that are attached by suitable fittings to the open ends of ports in the cover 65. Distribution of the hydraulic fluid or oil among the ports of the member BB is controlled by the valve '54. This is diagrammatically illustrated in Fig. 6 where representations of the above mentioned parts are designated by their distinguishing reference characters. As will appear from said diagram, the slide valve 64 is ofthe multiple spool type, having at about its longitudinal center a relatively narrow circumferential groove 64* and, spaced in opposite directionstherefrom, relatively wide circumferential grooves N and 64, the wide grooves being separated from the former narrow groove by the respective lands 64 and 6-4 Toward its ends, beyond. the wide grooves, the valve is provided with lands 6M and 64 As disclosed in. the diagram, the. outlet of. the pump communicates with a port. Sl'll in. the body member till thatv is elongated. and overlies to some extent the lands 64 and 64 oi; the valve, when the latter is. in neutral. position; Under theseconditions, this port. 60* also communicates. through the groove: 64 of the valve, with. aport 60 through which liquid is returned to. the tank; 66; and branches 60 and till lead oiffrom the port 54 and havev their. ends remote therefrom closed by the lands 64 and 64 As. shown. only in the diagram, a relief. valve T5. is included; in a return connection between. theoutletzof the pump and the tank. The previously mentioned: conduits or hoses 68 and. 69 commimicata. through ports 60* and 692 with: the wide circumferential grooves 641*- and 64; respectively, of the valve. The conduit or hose-68 leads to the upper end: of the cylinder 31, while the other conduit: orhose 69 leads to the lowerend ofsaidcylinder;

The slide valve 54 extends forwardly of. the body member 60 and is pivotally connected to a; valve operating lever or handle- 80; The lower end of this handle is mounted: for oscillation on a pivot member or" bolt 8i that isrcarried by theplate 57,. and applied. to the opposite: end of the handle is a hand grip 83. The: valve 64,. shown". in Fig. 6 in neutral or central position, is adaptied to be moved by the handle: 80; in a forward direction in opposition to a. compression. spring: 85, or in a rearward direction. in opposition to. a similar spring 86, said; springs tending. to hold: the valve, as well as-thehandle 80, in neutralor what may be regarded. normal position; The handle 89) is ordinarily restrained against movement ina forward direction. by a latch designated generally by the numeral 88;. This latch: includes a mounting bracket 90 thatis fastened to the top of the cover- 65 and? includes a barrel 92' within theend" of which, adj acent' the handle 80-; a plunger 93" is guided. As" appears in Fig. 5, the inner end of the plunger 93 has an: axial recess within which is secured; by aset screw 94', the end of a relatively stiff'wire 951. Locked a set screw 96 within the opposite end ofthebarrel is. a bushing. 91. Projected inwardly through the bore ofthis bushing, and. fastened. therein. as by the" previously mentioned: set screw 96, is the end portion of a fiexiblesheathz I 00, these-zine: being. in the nature of a tightly wound. helical spring. Theen'd of the sheath distant from the:

latchis secured to a' hanger I 02; shown as fastened, by a bolt 63, to the front ofthemacliine table" H5. The previouslymentionedwire 95 ex*- tends through the sheath" Hi0 and projects be-' yond the hanger 102 where it has fastened to it a knob-like actuator H15. A coiled spring" I'U'IJ, enclosed by the barrel. 92, is compressed between the plunger 93 and the bushing. 91 and normally projects the plungerv frontof' the handle. 80'. so as to prevent. the latter from. being swung foriwardly- It is obvious. from. the construction. de-

scribed that the: plunger. is retractedaagainstthe 75.

6 action. of the. spring. 95 by pulling the actuator I05 forwardly.

Mounted in a convenient place; on. the frame of the paper cutter, as upon the side member I I: adjacent the table l 5 is an electric switch H6 that is in circuit with the motor 53 by electrical conductors (not shown). When the switch is operated to close the circuit, the motor-will be energized and drive the pump 62 to draw liquid or oil. from the tank 66 and deliver it to the port 66 (Fig; 6) of the" body member 60; Assuming. the valve to be in neutral. position; this portcommunicates, through: the. groove 64 and. port 50 with. the tank. 66. Thus, with the pump idling, so tospeak, the liquid or oil is circulated throughthe path. described without efiect.

In. considering an operation of the paper: outtor, it will be assumed that a stack of paper sheetshas been. placed upon the table 15' against; the back gauge 23; that said. gauge hasv been moved forwardly the desired distance by manipulation of. the hand: wheel 25 to position thesheets for cutting, and that the stack has been clamped in such. position by the turning of the wheel 26. The machine may now be operated to cut the material by pulling forwardly" on the actuator I05 by means of the right hand, and depressingthe handle with the left hand. This will result in. shifting: the valve 64 forwardly (to the right, as viewed in Fig. 6) so as to'shut off the port 62 through which the liquid or oil is returned? to the tank, and establish communication between the port 60 and the port 60 through the wide groove 64 of the valve. At

' the same time the port 69 through the other wide groove 64, is placed in communication with the branch 68 of the port 60'". Therefore, with the valve in forward position, pressure fluid is delivered from the pump through the conduit or hose 68 to the upper end of the cylinder 3|, while the liquid or oil in the lower end of the cylinder is permitted to escape through the conduit or hose 61% to the tank. The handle 80 is-held forward until the piston 32 is stopped at the lower end of the stroke, which means that the knife 20' passed through the material onthe table [5- and engaged the cutting stick I6. If, for any reason, it should be desired to stop the knife before it reaches the bottom of its stroke, this may be accomplished by returning the handle 80' to' normal position wherein it may be held by the latch 88111301} release of the actuator I 05. Under these conditions the pump idles and circulates the oil or liquid. as previously described,.

while the. liquid or oil contained in the opposite ends of the cylinder 3'! is locked therein. Obvi ously, the stroke of the knife may be completed by releasing the'latch 88- and. swinging the handle:

80' forwardly; One reason for stopping the knife before it reaches the bottom of its stroke, as I have hereinbefore mentioned, is to facilitate the removal and replacement of the knife, or its adjustmentwith respect to the knife bar. In a normal cutting operation, however, there is no incentive for stopping the knife on its downward" stroke before the cut is completed.

When the knife is to be lifted, the handle 80 is swung rearwardly so as to shut off the port 60 and establish communication between the ports Ell and 60 on the one hand (thereby to deliver pressure. fluid to the lower end of the cylinder 3i),v and,- on the other hand, between the ports 60 and the branch port 60- (to permitreturmof 7 the liquid from the upper end of the cylinder'to' the tank).

As I have previously explained, a' dangerous situation is created if the knife bar is stopped on its return stroke before it attains an elevation wheerin the cutting edge of the knife is above the bottom plane of the clamp 2?. Otherwise the operator might engage one or both of his hands with'the edge of the knife in attempting to remove a shallow stack of material from beneath the knife or in rearranging the stack for further cutting. To avoid such an occurrence, I have included a contrivance that automatically functions to hold the valve operating handle 88 in its rearward position until the knife reaches the top limit of its stroke. In the present instance I have provided an hydraulically operated means for accomplishing this end, although I consider changes and modifications of said'contrivance within the scope of my invention provided that they. are embraced by the terms of the appended claims. The present preferred embodiment of this feature of the invention is illustrated in structural detail'in '7 and 8, and diagrammatically in Fig. 6.

Mounted upon the cover 65 that is a part of the hydraulic unit is a support III! to which is pivoted, at III, a latch bar H2. The forward end of this bar is shown as reduced in thickness and is provided, on its under side, with a notch H5, for the reception of a projection M5 on the valve operating arm 80 when said arm is swung to its rearward position. Attached to the support I It beneath the latch bar H2 is a rectangular body member I which has, adjacent its forward end, a vertical bore I 2i that opens through the top of said body member and contains a piston-like plunger I22, shown as fitted with a conventional O-ring I23 to prevent leakage of pressure fluid about the plunger. The lower end of the bore I 2 I is placed in communication, through a port I25, with a fitting I26, and a pipe I21 communicatively connects this fitting with one designated I28. The latter fitting opens into the pressure fluid passage of the hydraulic unit wherewith the conduit or hose 59 constantly communicates, wherefore the bore I2I is in communication at all times with the lower end of the cylinder 3|, as diagrammatically illustrated in Fig. 6. EX- cepting when the valve operating handle 85] is in its rearward position, the lower edge of the nose of the latch bar I I2 rides on the projection I I5 of said handle, and the bar is rocked in a direction to engage the notch I I 5 with said projection by a spring I38 that occupies a top-opening recess I3! of the body member IZG and bears, at its'upper end, against the overlying portion of the latch bar.

It is evident from the foregoing that when the handle 80 is swung rearwardly to bring about the elevation of the knife bar in the manner above described, it will be held in such position by the latch bar II2 until the forward end of said bar is elevated against the action of the spring I by the plunger I 22. This occurs after the piston 3i is stopped at the upper end of its stroke and pressure builds up within that portion of the system wherewith the bore I2I communicates sufficient to overcome the tension of said spring I30 and, through the plunger I22, lift the latch bar II2 thereby to liberate the projection H5 and allow the operating handle 88 to resume normal position.

Obviously, the tension of the spring I30 is somewhat less than that of the'spring that is inorporated in the relief valve I5 and which tendsto 8, maintain the latter valve closed. This insures release of the handle before the valve 15 opens to permit i'dle'circulation of the fluid through the pump and tank.

Having thus described my invention, what I claim is:

1. In a paper cutter including a knife that is supported substantially horizontally for up-anddown movement, hydraulic equipment for raising and lowering the knife, a member movable from a neutral position to a first operative position for causing said equipment to lower the knife and to i a second'operative position for causing the equipment to raise the knife, means tending to retain said member in neutral position, a movable latch element for cooperation with said member and that is biased in a direction to engage and hold said member in'second operative position, and means rendered effective when the knife reaches the top of its stroke to actuate the latch element and release said member.

2.'In a paper cutter including a frame, and a knife supported substantially horizontally therein for up-and-down movement; a cylinder, and a pistonreciprocable in the cylinder, the one bemg attached to the frame and the other having operative connection with the knife, a pressure fiuid'power unit, fluid conveying means including two branches leading from said unit to the respective ends of the cylinder, a distributor valve for controlling flow of pressure fluid through said branches, an operating member for said valve movable from a neutral position to a first operativ position to effect, through the medium of said valve, delivery of pressure fluid through one branch to the appropriate end of the cylinder to cause the knife to be lowered and to a second 010- erative position to similarly effect delivery of pressure fluid through the other branch to the opposite end of the cylinder to cause the knife to be raised, a latch biased to holding position for retaining the operating member in second position, and pressure operated means in communication with the last mentioned branch for releasing said latch when the pressure of the fluid in said last mentioned branch exceeds that required toraise the knife.

3. Hydraulic equipment for use with prevailing paper cutters, the same including a cylinder and piston-assembly adapted for installation in a paper cutter in substitution for the manual knife operating mechanism thereof, and a power unit assembly providing a source of pressure fluid, a control handle incorporated in and supported solely by said power unit assembly, a latch carried by the power unit assembly for normally restraining said handle from assuming s, given position wherein it causes the equipment to function to lower the knife, an actuator for said latch, said handle being shiftable to a second operative position in which it causes the equipment to operate in a manner to raise the knife, fluid conducting means establishing a, communication between the power unit assembly and the cylinder of the first mentioned assembly, said power unit assembly being adapted to be arranged in such relation to the paper cutter that said handle is adjacent the table thereof, the aforesaid latch actuator being adapted to be supported in substantially spaced relation to said handle but so that both it and the handle may be reached simultaneously by the two hands of an operator, a second latch biased to holding position for retaining said handle in said second operative position, and pressure operated means e communication with a part of the fluid conducting means wherein pressure prevails during the raising of the knife and which pressure operated means acts to release the second latch when the pressure exceeds that required to raise the knife.

4. Hydraulic equipment for incorporation-in a paper cutter of the character described, said equipment including a cylinder and piston assembly adapted for pivotal connection at one end to the center frame of the paper cutter below the table thereof and at the other end to the knife bar operating part of the cutter with its axis disposed approximately in the direction of movement of said part, the piston being moved in a direction to lower the knife bar when pressure fluid is delivered to the so-called working end of the cylinder, and in a direction to lift said bar when pressure fluid is delivered to the opposite end of the cylinder, a power unit assembly adapted to be positioned in convenient relation to the paper cutter, the same comprising a tank for liquid, a pump, an electric motor, driving connections between the motor and pump, said pump having an inlet communicating with said tank and provided also with an outlet, liquid conducting means leading from said outlet and including two branches, the first branch being communicatively connected to the working end of the cylinder and the second branch to the opposite end thereof, a valve incorporated in said power unit assembly and located in said liquid conducting means, said valve having three positions in the first of which it cuts off flow to said branches, in the second of which it direct flow to the first branch and establishes communication between the second branch and the tank, and in the third of which it directs flow to the second branch and establishes communication between the first branch and the tank, means for operating the valve including a handle adapted to be located adjacent the table of the machine, latch mechanism cooperating with said valve operating means and biased to a position wherein it restarins said operating means from moving the valve to second position, an actuator for said latch means adapted to be supported in a position enabling an operator to simultaneously rasp it with one hand and the handle of the aforesaid valve operating means with the other hand, holding means biased toward effective position for retaining the valve in the third position, and pressure operated means in communication with said second branch for releasing said holding means when pressure in said second branch exceeds that required to lift the knife bar.

5. Hydraulic equipment for a paper cutter, said equipment including a cylinder and piston assembly adapted for operative connection with the knife of the cutter, a power unit assembly providing a source of pressure fluid, communicative connections between said assemblies, control means for the power unit assembly including a movable handle normally biased to a neutral position, a latch biased to holding position for restraining said handle from assuming a first operative position wherein it causes the equipment to function to lower the knife, manually operated means for releasing said latch, a second latch biased toward holding position for retaining the handle in a second operative posit-ion wherein it causes the equipment to function to raise the knife, and means automatically operated when the knife reaches the top of its stroke for releasing the second latch.

6. In a paper cutter including a frame, and a knii sii pbrijss u'b ant si hor z ntal he iPl' i Qld'F Q-WI WPVE IE IP a cylinder, and s .ni esrg r ab zin thge l nd t o en a tach d?! th ame and hec having operative connect onwith the knife, a pressure fluid er unit jfil id. con e i me n includingtwo bra-riches ;;lead1rig from said unit to the respective endso'f the cylinder, a distributor valve for controlling flow of pressure fluid through said branches, an operating member for said valve movable from a neutral position to a first operative-position to effect, through the medium of said. valve, delivery of pressure fluid through one branch to the appropriate end of the cylinder to cause the knife to be lowered and to a second operative position to similarly effect delivery of pressure fluid through the other branch to the opposite end of the cylinder to cause the knife to be raised, a latch biased to holding position for retaining the operating member in second position, and. means automatically operated when the knife reaches the top of its stroke for releasing the second latch.

'7. Hydraulic equipment for incorporation in a paper cutter of the character described, said equipment including a cylinder and piston assembly adapted for pivotal connection at one end to the center frame of the paper cutter below the table thereof and at the other end to the knife bar operating part of the cutter with its axis disposed approximately in the direction of movement of said part, the piston being moved in a direction to lower the knife bar when pressure fluid is delivered to the so-called working end of the cylinder, and in a direction to lift said bar when pressure fluid is delivered to the opposite end of the cylinder, a power unit assembly comprising a tank for liquid, a pump, an electric motor, driving connections between the motor and pump, said pump having an inlet communicating with said tank and provided also with an outlet, liquid conductin means leading from said outlet and including two branches, the first branch being communicatively connected to the k working end of the cylinder and the second branch to the opposite end thereof, a valve incorporated in said power unit assembly and lo cated in said liquid conducting means, said valve having three positions in the first of which it cuts off flow to said branches, in the second of which it directs flow to the first branch and establishes communication between the second branch and the tank, and in the third of which it directs flow to the second branch and establishes communication between the first branch and the tank, means for operating the valve including a handle adapted to be located adjacent the table of the machine, latch mechanism cooperating with said valve operating means and biased to a position wherein it restrains said operating means from moving the valve to second position, an actuator for said latch means adapted to be supported in a position enabling an operator to simultaneously rasp it with one hand and the handle of the aforesaid valve operating means with the other hand, holding means biased toward effective position for retaining the valve in the third position, and means automatically operated when the knife reaches the top of its stroke for releasing said holding means.

8. The combination with a paper cutter having a movable knife and pressure means for moving the knife in cutting and return directions including a source of pressure for said pressure means and a valve to control said pressure, of means for actuating said valve comprising, manual means for moving said valve from a neutral position to either knife cuttin or return positions, separate manually releasable means for holding said valve against knife cutting movement, and automatic means for holding said valve in knife return position, said automatic holding means being released upon movement of the knife to the end of its return movement.

JOSEPH ADRIAN.

References Cited in the file of this patent UNITED STATES PATENTS Number 5 893,166 918,120 1,200,802 2,379,171

10 Number Name Date Hand July 14, 1908 Bradmiller Apr. 13, 1909 Berry Oct. 10; 1916 McLaughlin June 26, 1945 FOREIGN PATENTS Country Date England Nov. 30. 1933 

